There are many speaker products that have been installed in alarm systems to warn occupants in a region of a life safety threat. This can include fire or other safety threats. The speaker can be used to annunciate a sound to indicate evacuation or to provide voice instructions to the occupants.
However, it can become important for occupants to quickly identify their egress path to evacuate the building. Known speaker systems mount on walls or ceilings and often do not provide any directional indications. In addition, speaker systems using voice must coordinate the different speakers to prevent distortion due to sounds from different speakers being heard at the same time. Even if the message is the same, the phase delays in sound propagation from one speaker location to another speaker location can be substantial thereby causing distortion for the occupant. This can be an important issue during stressful situations.
In one known technology speaker systems use a multi-frequency sounder with sound similar to white noise and occupants are more able to identify that speaker's location to egress towards it. The occupant can easily distinguish its direction even with sound reflections. However, a long hallway may require multiple sounders. In this circumstance, the occupant doesn't know which sounder to egress towards. The use of fire doors can be an expensive approach to overcome this problem wherein the fire doors control the sound propagation in the hallways.
It would be desirable to provide directional speakers such that an occupant in a hallway will always hear the loudest sounds to guide him/her in egressing from the building, even with multiple speakers. A fast escape maybe necessary to preserve life since hazardous gases (carbon monoxide for example) may be present in addition to smoke.